Simsima eSIM Data Plans for Japan

Simsima does not offer a true unlimited data eSIM plan for Japan. The plans listed under the name “Unlimited” actually provide 3 GB of high‑speed data per day; once that daily allowance is reached the speed drops to 1000 kbps.

Travelers who need larger data allowances can choose fixed‑data alternatives. For example, Simsima sells a 100 GB plan valid for 180 days and a 50 GB plan valid for 30 days, both of which include high‑speed 5G data with no daily or overall limit before throttling. These fixed‑data options give more predictability for heavy data use and may be more cost‑effective for longer stays.

Simsima does not provide a phone number or SMS capability on its Japan eSIM plans; only data‑only plans are available. Travelers can still use VoIP applications such as WhatsApp, Telegram, and iMessage over the data connection for calls and messaging, but they should check that these services are accessible in Japan before purchasing.

Simsima provides 11 single‑country data plans that cover Japan and 19 multi‑country plans that include Japan as part of a broader package. The available plans range in price from approximately $0.40 to $84.53 and in data allowance from 100 MB up to 100 GB per validity period, which can last between 5 and 180 days. For Japan‑specific offers, customers can choose between plans that have a fixed data cap—such as 1 GB, 3 GB, 5 GB, 10 GB and 20 GB—or plans that apply a daily data cap, for example 200 MB per day or 1 GB per day, allowing more flexible usage over the plan’s duration. The mix of fixed and daily cap options offers users the ability to select a plan that best matches their travel data needs.